Visible light and ultraviolet radiation are commonly called shortwave radiation, while infrared radiation is referred to as longwave radiation. The Sun radiates energy mainly in the form of visible light, with small amounts of ultraviolet and infrared radiation. For this reason, solar radiation is usually considered shortwave radiation.

The Earth produces virtually no visible light, or ultraviolet radiation. Almost all of the natural radiation created by the Earth is infrared, or heat. Thus, we refer to the terrestrial radiation as longwave radiation.